This invention relates to a polymer-clay nanocomposite having an improved gas permeability comprising (i) a melt-processible matrix polymer, and incorporated therein (ii) a layered clay material intercalated with a mixture of at least two organic cations. The invention also relates to processes for preparing a nanocomposite and articles produced from a nanocomposite.

This invention relates generally to a polymer-clay nanocomposite having improved gas barrier comprising a clay material intercalated with a mixture of organic cations. This invention further relates to articles produced from the nanocomposite, and a process for preparing a nanocomposite.
There is much interest in layered clay-based polymer nanocomposites because of the improved properties exhibited by the nanocomposites. It is desirable to maximize delamination of the layered clay material into individual platelet particles in order to maximize some property improvements, including barrier (gas permeability) improvements, and to minimize deleterious effects on some properties including elongation-at-break. Ideally, the clay material is exfoliated into platelet particles with a thickness of less than about 20 nm in order to achieve clarity that is comparable to the clay-free polymer. To date, the only polymer/clay nanocomposites that meet this expectation are prepared by incorporation of organically treated clays during synthesis of the polymer from monomer. It is widely known, however, that the amount of clay that can be admixed in a polymer and still exhibit exfoliation of the layered clay is limited and some mechanical properties, such as elongation-at-break, are often reduced considerably upon the addition of the clay.
Researchers recognized the value of inventing melt-compounding processes that provide exfoliated clay composites. Namely, melt-compounding processes provide more versatility of polymer choice and clay loading and the potential for cost savings. However, with many polymer/clay mixtures, the melt compounding processes explored to date do not provide sufficient exfoliation of the platelet particles.
Polyesters such as poly(ethylene terephthalate) (PET) are widely used in bottles and containers which are used for carbonated beverages, fruit juices, and certain foods. Useful polyesters have high inherent viscosity (I.V.), which allows polyesters to be formed into parisons and subsequently molded into containers. Because of the limited barrier properties to oxygen, carbon dioxide and the like, PET containers are not generally used for products requiring long shelf life. For example, oxygen transmission into PET bottles which contain beer, wine and certain food products causes these products to spoil. There have been attempts to improve the barrier properties of PET containers by the use of multilayer structures comprising one or more barrier layers and one or more structural layers of PET. However, multilayer structures have not found wide use and are not suitable for use as a container for beer due to the high cost, the large thickness of the barrier layer required, and poor adhesion of the barrier layer to the structural layer.
There are many examples in the patent literature of polymer/clay nanocomposites prepared from monomers and treated clays. For example, U.S. Pat. No. 4,739,007 discloses the preparation of Nylon-6/clay nanocomposites from caprolactam and alkyl ammonium-treated montmorillonite. U.S. Pat. No. 4,889,885 describes the polymerization of various vinyl monomers such as methyl methacrylate and isoprene in the presence of sodium montmorillonite.
Some patents describe the blending of up to 60 weight percent of intercalated clay materials with a wide range of polymers including polyamides, polyesters, polyurethanes, polycarbonates, polyolefins, vinyl polymers, thermosetting resins and the like. Such high loadings with modified clays are impractical and useless with most polymers because the melt viscosities of the blends increase so much that they cannot be molded.
WO 93/04117 discloses a wide range of polymers melt blended with up to 60 weight percent of dispersed platelet particles. WO 93/04118 discloses nanocomposite materials of a melt processable polymer and up to 60 weight percent of a clay that is intercalated with organic onium salts. The use of clays intercalated with a mixture of onium ions is not contemplated or disclosed.
U.S. Pat. No. 5,552,469 describes the preparation of intercalates derived from certain clays and water soluble polymers such as polyvinyl pyrrolidone, polyvinyl alcohol, and polyacrylic acid. The use of clays intercalated with organic cations is specifically excluded.
JP Kokai patent no. 9-176461 discloses polyester bottles wherein the polyester contains umnodified sodium montmorillonite. Incorporation of the clay into the polyester by melt compounding is disclosed; however, the use of clays intercalated with a mixture of organic cations is neither contemplated nor disclosed.
Clays intercalated with a mixture of organic cations, typically onium ions, are used as rheology modifiers for certain coating applications; however, their use in polymer/clay nanocomposites has been neither contemplated nor disclosed. The following references are of interest with regard to chemically modified organoclay (clay/organic cation intercalate) materials: U.S. Pat. Nos. 4,472,538; 4,546,126; 4,676,929; 4,739,007; 4,777,206; 4,810,734; 4,889,885; 4,894,411; 5,091,462; 5,102,948; 5,153,062; 5,164,440; 5,164,460; 5,248,720; 5,382,650; 5,385,776; 5,414,042; 5,552,469; WO Pat. Application Nos. 93/04117; 93/04118; 93/11190; 94/11430; 95/06090; 95/14733; D. J. Greenland, J. Colloid Sci. 18, 647 (1963); Y. Sugahara et al., J. Ceramic Society of Japan 100, 413 (1992); P. B. Massersmith et al., J. Polymer Sci.: Polymer Chem., 33, 1047 (1995); C. O. Sriakhi et al., J. Mater. Chem. 6, 103(1996).
Therefore, as shown above, a need still exists for a polymer nanocomposite comprising a clay material and articles produced therefrom that have improved barrier properties.
It has been found that clays intercalated with a mixture of organic cations, preferably onium ions, are useful for the preparation by a melt compounding process of a polymer/clay nanocomposite with sufficient exfoliation and molecular weight for improved properties and clarity for commercial applications, including film, bottles, and containers. The polymer nanocomposite of this invention is particularly useful for forming packages that have improved gas. barrier properties. Containers made from these polymer composite materials are ideally suited for protecting consumable products, such as foodstuffs, soft drinks, and medicines.
This invention also seeks to provide a cost-effective method for producing barrier layers with sufficient oxygen barrier and clarity for wide spread applications as multilayer bottles and containers, including beer bottles.
In accordance with the purpose(s) of this invention, as embodied and broadly described herein, this invention, in one embodiment, relates to a polymerclay nanocomposite having an improved gas permeability comprising (i) a melt-processible matrix polymer, and incorporated therein (ii) a layered clay material intercalated with a mixture of at least two organic cations.
In another embodiment, this invention relates to a process for preparing a polymer-clay nanocomposite comprising (i) preparing an intercalated layered clay material by reacting a swellable layered clay material with a mixture of at least two organic cations, and (ii) incorporating the intercalated clay material in a matrix polymer by melt processing the matrix polymer with the intercalated clay.
In yet another embodiment, this invention relates to a process for preparing a polymer-clay nanocomposite having an improved gas permeability comprising the steps of: (i) preparing an intercalated layered clay material by reacting a swellable layered clay material with a mixture of at least two organic cations, (ii) adding the clay material to components for forming a polymer, and (iii) conducting the polycondensation polymerization of the components in the presence of the clay material.
Additional advantages of the invention will be set forth in part in the detailed description, which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory of preferred embodiments of the invention, and are not restrictive of the invention, as claimed.
The present invention may be understood more readily by reference to the following detailed description of the invention and the examples provided therein. It is to be understood that this invention is not limited to the specific processes and conditions described, as specific processes and/or process conditions for processing polymer articles as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.
It must also be noted that, as used in the specification and the appended claims, the singular forms xe2x80x9ca,xe2x80x9d xe2x80x9canxe2x80x9d and xe2x80x9cthexe2x80x9d included plural references unless the context clearly dictates otherwise.
Ranges may be expressed herein as from xe2x80x9caboutxe2x80x9d or xe2x80x9capproximatelyxe2x80x9d one particular value and/or to xe2x80x9caboutxe2x80x9d or xe2x80x9capproximatelyxe2x80x9d another particular value. When such a range is expressed, another embodiment includes from the one particular and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent xe2x80x9cabout,xe2x80x9d it will be understood that the particular value forms another embodiment.
Whenever used in this specification, the terms set forth shall have the following meanings:
xe2x80x9cLayered clay,xe2x80x9d xe2x80x9clayered clay materialxe2x80x9d or xe2x80x9cclay materialxe2x80x9d shall mean any organic or inorganic material or mixtures thereof, such as a smectite clay mineral, which is in the form of a plurality of adjacent, bound layers. The layered clay comprises platelet particles and is typically swellable.
xe2x80x9cPlatelet particles,xe2x80x9d xe2x80x9cplateletsxe2x80x9d or xe2x80x9cparticlesxe2x80x9d shall mean individual or aggregate unbound layers of the layered clay material. These layers may be in the form of individual platelet particles, ordered or disordered small aggregates of platelet particles (tactoids), and small aggregates of tactoids.
xe2x80x9cDispersionxe2x80x9d or xe2x80x9cdispersedxe2x80x9d is a general term that refers to a variety of levels or degrees of separation of the platelet particles. The higher levels of dispersion include, but are not limited to, xe2x80x9cintercalatedxe2x80x9d and xe2x80x9cexfoliated.xe2x80x9d
xe2x80x9cIntercalatedxe2x80x9d or xe2x80x9cintercalatexe2x80x9d shall mean a layered clay material that includes an intercalant disposed between adjacent platelet particles or tactoids of the layered material to increase the interlayer spacing between the adjacent platelets and tactoids. In this invention, the intercalant is preferably a mixture of 2 or more different types of organic cations.
xe2x80x9cExfoliatexe2x80x9d or xe2x80x9cexfoliatedxe2x80x9d shall mean platelets dispersed predominantly in an individual state throughout a carrier material, such as a matrix polymer. Typically, xe2x80x9cexfoliatedxe2x80x9d is used to denote the highest degree of separation of platelet particles.
xe2x80x9cExfoliationxe2x80x9d shall mean a process for forming an exfoliate from an intercalated or otherwise less dispersed state of separation.
xe2x80x9cNanocomposite(s)xe2x80x9d or xe2x80x9cnanocomposite composition(s)xe2x80x9d shall mean a polymer or copolymer having dispersed therein a plurality of individual platelets obtained from a layered clay material.
xe2x80x9cMatrix polymerxe2x80x9d shall mean a thermoplastic or melt-processible polymer in which the platelet particles are dispersed to form a nanocomposite. In this invention, however, the platelet particles are predominantly exfoliated in the matrix polymer to form a nanocomposite.
The present invention relates generally to melt compounding processes to prepare polymer/clay nanocomposite compositions and to certain polymer/clay nanocomposite compositions wherein the clay particles are treated with a mixture of two or more organic cations, preferably organic cation salts. The polymer/clay nanocomposites of this invention exhibit an unexpectedly lower gas permeability, especially oxygen permeability, than other layered polymer/clay nanocomposites prepared by melt compounding processes. The process of this invention may be used to prepare a wide variety of polymer/clay nanocomposite compositions.
The prior art has defined the degree of separation of platelet particles based on peak intensity and basal spacing value, or lack of predominant basal spacing, as determined by X-ray analyses of polymer-platelet composites. Even though X-ray analysis alone often does not unambiguously predict whether or not the platelet particles are individually dispersed in the polymer, it can often allow quantification of the level of dispersion achieved. As such, X-ray analysis only provides information related to the well-ordered aggregates, which are only a small portion of the platelet particles present. Moreover, in polymer nanocomposites, X-ray analysis alone does not accurately predict the dispersion of the platelet particles in neither the polymer nor the resultant gas barrier improvement. TEM images of polymer-platelet composites show that platelet particles which are incorporated into at least one polymer exist in a variety of forms, including, but not limited to, individual platelets (the exfoliated state), disordered agglomerates of platelets, well ordered or stacked aggregates of platelets (tactoids), swollen aggregates of stacked platelets (intercalated tactoids), and aggregates of tactoids.
Without being bound by any particular theory, it is believed that the degree of improved gas barrier (permeability) depends upon the embodiment ratio of the resulting particle platelets and aggregates, the degree to which they are dispersed or uniformly distributed, and the degree to which they are ordered perpendicular to the flux of the permeant.
To obtain the improvements in gas permeability according to the present invention, it is preferable that the platelet particles representative of the bulk of the composite be exfoliated, and preferably be highly exfoliated, in the matrix polymer such that the majority, preferably at least about 75 percent and perhaps as much as at least about 90 percent or more of the platelet particles, be dispersed in the form of individual platelets and aggregates having a thickness in the shortest dimension of less than about 20 nm and preferably less than about 10 nm, as estimated from TEM images. Polymer-platelet nanocomposites containing more individual platelets and fewer aggregates, ordered or disordered, are most preferred. Significant levels of incomplete dispersion (i.e., the presence of large agglomerates and tactoids greater than about 20 nm) not only lead to an exponential reduction in the potential barrier improvements attributable to the platelet particles, but also can lead to deleterious affects to other properties inherent to polymer resins such as strength, toughness, and heat resistance.
Again, without being bound by a particular theory, it is believed that delamination of platelet particles upon melt processing or mixing with a polymer requires favorable free energy of mixing, which has contributions from the enthalpy of mixing and the entropy of mixing. Melt processing clay with polymers results in a negative entropy of mixing due to the reduced number of conformations, which a polymer chain has when it resides in the region between two layers of clay. It is believed that poor dispersion is obtained using melt-processible polyesters, for example, because the enthalpy of mixing is not sufficient to overcome the negative entropy of mixing. In contrast, generally good dispersions are obtained with polyamides due to their hydrogen bonding character. However, the extent of this dispersion is frequently lessened because of the negative entropy of mixing. Heretofore, efforts to achieve a favorable enthalpy of mixing of platelet particles with melt processible polymers by pretreating the platelet particles (e.g., by cation exchange with alkyl ammonium ions) have been unsuccessful.
Regarding the present invention, it has been found that using clay intercalated with a mixture of organic cations while melt processing with a polymer gives good dispersion in a resulting nanocomposite, creating mostly individual platelet particles and improving the gas permeability of the nanocomposite. By using a mixture of organic cations (or mixed tethers), a balance of polar and non-polar groups may be achieved without conducting difficult syntheses, for example. That is, it is also easier to mix known and available cations (tethers) than to design and synthesize new ones.
Again without being bound by any particular theory, it is believed that given that a polymer chain typically comprises areas with different character (such as hydrophobicity, polarity, hydrogen bonding character, etc.), the use of a mixture of organic cations (mixed tethers) may help the polymer to achieve lower enthalpy of mixing by providing materials of different polarity for interaction with different parts of the polymer chain. To take advantage of this, the chain should have sufficient mobility and entropy to assume a conformation that is favorable, and expanding the clay gallery and delaminating into individual platelet particles helps this. An additional theory is that a mixture of cations (two or more tethers) might prefer to associate with a given polymer rather than with each other. The above rationales pertain primarily to the enthalpy. However, other theories are plausible.
In order to maximize the degree of exfoliation of the onium ion-treated clays in melt polymers, it is essential to have good compatibility between the matrix polymer (or oligomer, or polymer reactants) and the onium ions that are ion-exchanged at the clay platelet surface. In other words, the selection of the onium ions is based on the compatibility of the onium ions with the matrix monomers oligomers and polymers. Without being bound by any particular theory, it is believed that the formation of the mixed onium-ion exchanged clays enhances the compatibility of the gallery, between adjacent platelets, with the matrix polymer. Also, mixed onium ions could increase the compatibility range of a nanomer gallery with the matrix polymer. Mixed onium ion-intercalated clays can be used in the PET polymerization process to prevent the collapse of the exfoliated clay particles during the polymerization of ethylene glycol and DMT in the PET synthesis process. The polarity of the matrix polymer, e.g., PET, decreases as the degree of polymerization increases. The initial exfoliated clay in ethylene glycol may not be compatible with the PET matrix polymer using a single, high polarity onion ion. However, by incorporation of low polarity surfactants (onium ions) as well as higher polarity onium ions, in the clay galleries prior to exfoliation in ethylene glycol, gallery collapse (platelet re-alignment) is avoided during polymerization of the PET.
By using the mixed onium ion-exchanged clay, one can reduce the amount of certain high molecular weight onium ions, and facilitate the particle size reduction process (lower weight of onium ions bonded to the platelet surfaces). For instance, ETHOQUAD 18/25, an ethoxylated ammonium ion, has a high molecular weight. For a fully ETHOQUAD 18/25-exchanged Nanomer, the content of silicate in the Nanomer will be less than 50 weight percent. Also the fully onium ion-exchanged Nanomer is difficult to de-water. By using 50:50 molar ratio of the ETHOQUAD 18/25:ODA (octadecylammonium), the amount of ETHOQUAD 18/25 in the final treated clay is reduced by 50 weight percent, the onium ion(s)-intercalated clay be can be easily de-watered, and the onium ion-intercalated clay is in a dry powder form, rather than a tacky material. The mixed ETHOQUAD 18/25-ODA-clay has better dispersion and exfoliation in the matrix polymer after extrusion, than that of any single fully treated ETHOQUAD 18/25-intercalated clay and ODA-intercalated clay. The better exfoliation will be translated into better O2 barrier properties.
More particularly, this invention relates to a polymer nanocomposite comprising a melt-processible polymer and up to about 25 weight percent of a swellable layered clay material which is intercalated with a mixture of at least two organic cations, preferably onium ions. The intercalated clay material has platelet particles, which are dispersed in the polymer. The polymer nanocomposite is preferably a polyester polymer or copolymer nanocomposite having an I.V. of at least 0.5 dL/g as measured in a mixture of 60 weight percent phenol and 40 weight percent 1,1,2,2-tetrachloroethane at a concentration of 0.5 g/100 ml (solvent) at 25xc2x0 C.
In one embodiment, the process for manufacturing the polymer nanocomposite of this invention comprises (1) preparing the intercalated layered clay material and (2) incorporating the intercalated layered clay material in a polymer by melt processing the polymer with the intercalated layered clay material. Melt processing includes melt and extrusion compounding. Use of extrusion compounding to mix the intercalated clay and the polymer presents two advantages. Chiefly, the extruder is able to handle the high viscosity exhibited by the nanocomposite material. In addition, in a melt mixing approach for producing nanocomposite materials, the use of solvents can be avoided. Low molecular weight liquids can often be costly to remove from the nanocomposite resin.
The first step of this invention is the preparation of the intercalated layered clay material by the reaction of a swellable layered clay with a mixture of organic cations, preferably ammonium compounds. The process to prepare the organoclay (intercalated clay) may be conducted in a batch, semi-batch, or continuous manner.
In another embodiment, the process of this invention comprises (i) preparing the intercalated layered clay material, (ii) adding the modified clay to a mixture of the components for forming the desired polymer and (iii) conducting the polycondensation polymerization in the presence of the modified clay. The molecular weight of the polymer material may be increased by any of a number of known approaches or by any combination of these approaches, e.g., chain extension, reactive extrusion, extrusion let-down, solid state polymerization or annealing, annealing under a flow of inert gas, vacuum annealing, let-down in a melt reactor, etc.
The resulting nanocomposite can then be processed into a desired barrier film or container with the processing procedures generally known in the art.
The nanocomposite of the present invention comprises less than about 25 weight percent, preferably from about 0.5 to about 20 weight percent, more preferably from about 0.5 to about 15 weight percent, and most preferably from about 0.5 to about 10 weight percent of clay. The amount of platelet particles is determined by measuring the amount of silicate residue in the ash of the polymer/platelet composition when treated in accordance with ASTM D5630-94. Useful clay materials include natural, synthetic, and modified phyllosilicates. Illustrative of such natural clays are smectite clays, such as montmorillonite, saponite, hectorite, mica, vermiculite, bentonite, nontronite, beidellite, volkonskoite, magadite, kenyaite, and the like. Illustrative of such synthetic clays are synthetic mica, synthetic saponite, synthetic hectorite, and the like. Illustrative of such modified clays are fluoronated montmorillonite, fluoronated mica, and the like. Suitable clays are available from various companies including Nanocor, Inc., Southern Clay Products, Kunimine Industries, Ltd., and Rheox.
Preferred clay materials are phyllosilicates of the 2:1 type having a cation exchange capacity of 0.5 to 2.0 milliequivalents per gram of mineral (meq/g). The most preferred clay materials are smectite clay minerals, particularly bentonite or montmorillonite, more particularly Wyoming-type sodium montmorillonite or Wyoming-type sodium bentonite.
Generally, the layered clay materials useful in this invention are an agglomeration of individual platelet particles that are closely stacked together like cards, in domains called tactoids. The individual platelet particles of the clays preferably have thickness of less than about 2 nm and diameter in the range of about 10 to about 3000 nm. Preferably, the clays are dispersed in the polymer so that most of the clay material exists as individual platelet particles, small tactoids, and small aggregates of tactoids. Preferably, a majority of the tactoids and aggregates in the polymer/clay nanocomposites of the present invention will have thickness in its smallest dimension of less than about 20 nm. Polymer/clay nanocomposite compositions with the higher concentration of individual platelet particles and fewer tactoids or aggregates are preferred.
Moreover, the layered clay materials are typically swellable free flowing powders having a cation exchange capacity between about 0.3 and about 3.0 meq/g, preferably 0.90 to 1.5 meq/g, and more preferably 0.95 to 1.25 meq/g. The clay may have a wide variety of exchangeable cations present in the galleries between the layers of the clay, including, but not limited to, cations comprising the alkaline metals (group IA), the alkaline earth metals (group IIA), and their mixtures. The most preferred cation is sodium; however, any cation or combination of cations may be used provided that most of the cations are exchanged for organic cations (onium ions) during the process of this invention.
Other non-clay materials having the above-described ion-exchange capacity and size, such as chalcogens, may also be used as the source of platelet particles under the present invention. Chalcogens are salts of a heavy metal and group VIA (O, S, Se, and Te). These materials are known in the art and do not need to be described in detail here.
The organic cation mixture used to intercalate the clay material of the nanocomposite of this invention is derived from organic cation salts, preferably onium salt compounds. Organic cation salts useful for the nanocomposite and process of this invention may generally be represented as follows:
wherein M is either nitrogen or phosphorous; X is a halide, hydroxide, or acetate anion, preferably chloride and bromide; and R1, R2, R3, and R4 are independently organic and oligomeric ligands or may be hydrogen.
Examples of useful organic ligands include, but are not limited to, linear or branched alkyl groups having 1 to 22 carbon atoms, more preferably 1 to 12 carbon atoms, aralkyl groups which are benzyl and substituted benzyl moieties including fused-ring moieties having linear chains or branches of 1 to 100 carbon atoms, more preferably at least one ligand with 12 or more carbons, in the alkyl portion of the structure, aryl groups such as phenyl and substituted phenyl including fused-ring aromatic substituents, beta, gamma unsaturated groups having six or less carbon atoms, and alkyleneoxide groups having 2 to 6 carbon atoms, more preferably 3 to 5 carbon atoms. Examples of useful oligomeric ligands include, but are not limited to, poly(alkylene oxide), polystyrene, polyacrylate, polycaprolactone, and the like.
Particularly useful organic cations for the organic cation mixture of this invention include, but are not limited to, alkyl ammonium ions, such as dodecyl ammonium, octadecyl ammonium, bis(2-hydroxyethyl) octadecyl methyl ammonium, octadecyl benzyl dimethyl ammonium, tetramethyl ammonium, and the like, and alkyl phosphonium ions such as tetrabutyl phosphonium, trioctyl octadecyl phosphonium, tetraoctyl phosphonium, octadecyl triphenyl phosphonium, and the like.
Illustrative examples of suitable polyalkoxylated ammonium compounds include the hydrochloride salts of polyalkoxylated amines available under the trade name JEFFAMINE (available from Huntsman Chemical), namely, JEFFAMINE-506, which is an oligooxyethlene amine with number average molecular weight of about 1100 g/mol, and JEFFAMINE 505 which is an oligooxypropylene amine with number average molecular weight of about 640 g/mol, and those available under the trade name ETHOQUAD or ETHOMEEN (available from Akzo Chemie America), namely, ETHOQUAD 18/25, which is octadecyl methyl bis(polyoxyethylene[15]) ammonium chloride, and ETHOMEEN 18/25, which is octadecyl bis(polyoxyethylene[15])amine, wherein the numbers in brackets refer to the total number of ethylene oxide units. The most preferred organic cations for use in polyesters, such as polyethylene terephthalates, are polyalkoxylated ammonium compounds.
Numerous methods to modify layered clays with organic cations are known, and any of these may be used in the process of this invention.
One embodiment of this invention is the modification of a layered clay with a mixture of organic cation salts by the process of dispersing a layered clay into hot water, most preferably from 50 to 80xc2x0 C., adding the organic cation salts separately or adding a mixture of the organic cation salts (neat or dissolved in water or alcohol) with agitation, then blending for a period of time sufficient for the organic cations to exchange most of the metal cations present in the galleries between the layers of the clay material. Then, the organically modified layered clay material is isolated by methods known in the art including, but not limited to, filtration, centrifugation, spray drying, and their combinations.
It is desirable to use a sufficient amount of the organic cation salts to permit exchange of most of the metal cations in the galleries of the layered particle for organic cations; therefore, at least about 0.5 equivalent of total organic cation salts is used and up to about 3 equivalents of organic cation salts can be used. It is preferred that about 0.5 to 2 equivalents of organic cation salts be used, more preferable about 1.0 to 1.5 equivalents. It is often desirable, but not required, to remove most of the metal cation salts and most of the excess organic cation salts by washing and other techniques known in the art.
The particle size of the resulting organoclay is reduced in size by methods known in the art, including, but not limited to, grinding, pulverizing, hammer milling, jet milling, and their combinations. It is preferred that the average particle size be reduced to less than 100 micron in diameter, more preferably less than 50 micron in diameter, and most preferably less than 20 micron in diameter.
Although not preferred, the clays may be further treated for the purposes of aiding exfoliation in the composite and/or improving the strength of the polymer/clay interface. Any treatment that achieves the above goals may be used.
Examples of useful treatments include intercalation with water-soluble or water-insoluble polymers, organic reagents or monomers, silane compounds, metals or organometallics, and/or their combinations.
Treatment of the clay can be accomplished prior to the addition of a polymer to the clay material, during the dispersion of the clay with a polymer or during a subsequent melt blending or melt fabrication step.
Examples of useful pretreatment with polymers and oligomers include those disclosed in U.S. Pat. Nos. 5,552,469 and 5,578,672, incorporated herein by reference. Examples of useful polymers for treating the mixed organic cation-intercalated clays include polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene glycol, polytetrahydrofuran, polystyrene, polycaprolactone, certain water-dispersible polyesters, Nylon-6 and the like.
Examples of useful pretreatment with organic reagents and monomers include those disclosed in EP 780,340 A1, incorporated herein by reference. Examples of useful organic reagents and monomers for intercalating the swellable layered clay include dodecylpyrrolidone, caprolactone, caprolactam, ethylene carbonate, ethylene glycol, bishydroxyethyl terephthalate, dimethyl terephthalate, and the like or mixtures thereof.
Examples of useful pretreatment with silane compounds include those treatments disclosed in WO 93/11190, incorporated herein by reference. Examples of useful silane compounds includes (3-glycidoxypropyl)trimethoxysilane, 2-methoxy (polyethyleneoxy)propyl heptamethyl trisiloxane, octadecyl dimethyl (3-trimethoxysilylpropyl) ammonium chloride and the like.
If desired, a dispersing aid may be present during or prior to the formation of the composite by melt mixing for the purposes of aiding exfoliation of the treated or untreated swellable layered particles into the polymer. Many such dispersing aids are known, covering a wide range of materials including water, alcohols, ketones, aldehydes, chlorinated solvents, hydrocarbon solvents, aromatic solvents, and the like or combinations thereof.
It should be appreciated that on a total composition basis, dispersing aids and/or pretreatment compounds may account for significant amount of the total composition, in some cases up to about 30 weight percent. While it is preferred to use as little dispersing aid/pretreatment compounds as possible, the amounts of dispersing aids and/or pretreatment compounds may be as much as about 8 times the amount of the platelet particles.
Any melt-processible polymer or oligomer may be used in this invention. Illustrative of melt-processible polymers are polyesters, polyetheresters, polyamides, polyesteramides, polyurethanes, polyimides, polyetherimides, polyureas, polyamideimides, polyphenyleneoxides, phenoxy resins, epoxy resins, polyolefins, polyacrylates, polystyrenes, polyethylene-co-vinyl alcohols (EVOH), and the like or their combinations and blends. Although the preferred polymers are linear or nearly linear, polymers with other architectures, including branched, star, cross-linked and dendritic structures, may be used if desired.
The preferred polymers include those materials that are suitable for use in the formation of multilayer structures with polyesters, and include polyesters, polyamides, polyethylene-co-vinyl alcohols (such as EVOH) and similar or related polymers and/or copolymers. The preferred polyester is poly(ethylene terephthalate) (PET) or a copolymer thereof. The preferred polyamide is poly(m-xylylene adipamide).
Suitable polyesters include at least one dibasic acid and at least one glycol. The primary dibasic acids are terephthalic, isophthalic, naphthalenedicarboxylic, 1,4-cyclohexanedicarboxylic acid and the like. The various isomers of naphthalenedicarboxylic acid or mixtures of isomers may be used, but the 1,4-, 1,5, 2,6-, and 2,7-isomers are preferred. The 1,4-cyclohexanedicarboxylic acid may be in the form of cis, trans, or cis/trans mixtures. In addition to the acid forms, the lower alkyl esters or acid chlorides may be also be used.
The matrix polymer of this invention may be prepared from one or more of the following dicarboxylic acids and one or more of the following glycols.
The dicarboxylic acid component of the polyester may optionally be modified with up to about 50 mole percent of one or more different dicarboxylic acids. Such additional dicarboxylic acids include dicarboxylic acids having from 6 to about 40 carbon atoms, and more preferably dicarboxylic acids selected from aromatic dicarboxylic acids preferably having 8 to 14 carbon atoms, aliphatic dicarboxylic acids preferably having 4 to 12 carbon atoms, or cycloaliphatic dicarboxylic acids preferably having 8 to 12 carbon atoms. Examples of suitable dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexanediacetic acid, diphenyl-4,4xe2x80x2-dicarboxylic acid, phenylenedi(oxyacetic acid), succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and the like. Polyesters may also be prepared from two or more of the above dicarboxylic acids.
Typical glycols used in the polyester include those containing from two to about ten carbon atoms. Preferred glycols include ethylene glycol, propanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, diethylene glycol and the like. The glycol component may optionally be modified with up to about 50 mole percent, preferably up to about 25 mole percent, and more preferably up to about 15 mole percent of one or more different diols. Such additional diols include cycloaliphatic diols preferably having 6 to 20 carbon atoms or aliphatic diols preferably having 3 to 20 carbon atoms. Examples of such diols include: diethylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, 3-methylpentanediol-(2,4), 2-methylpentanediol-(1,4), 2,2,4-trimethylpentane-diol-(1,3), 2-ethylhexanediol(1,3), 2,2-diethylpropane-diol-(1,3), hexanediol-(1,3), 1,4-di-(2-hydroxyethoxy)-benzene, 2,2b-is-(4-hydroxycyclohexyl)-propane, 2,4-dihydroxy-1,1,3,3-tetramethyl-cyclobutane, 2,2-bis-(3-hydroxyethoxyphenyl)-propane, 2,2-bis-(4-hydroxypropoxyphenyl)-propane and the like. Polyesters may also be prepared from two or more of the above diols.
Small amounts of multifunctional polyols such as trimethylolpropane, pentaerythritol, glycerol and the like may be used, if desired. When using 1,4-cyclohexanedimethanol, it may be the cis, trans or cis/trans mixtures. When using phenylenedi(oxyacetic acid), it may be used as 1,2; 1,3; 1,4 isomers, or mixtures thereof.
The polymer may also contain small amounts of trifunctional or tetrafunctional comonomers to provide controlled branching in the polymers. Such comonomers include trimellitic anhydride, trimethylolpropane, pyromellitic dianhydride, pentaerythritol, trimellitic acid, trimellitic acid, pyromellitic acid and other polyester forming polyacids or polyols generally known in the art. Suitable polyamides include partially aromatic polyamides, aliphatic polyamides, wholly aromatic polyamides and/or mixtures thereof. By xe2x80x9cpartially aromatic polyamide,xe2x80x9d it is meant that the amide linkage of the partially aromatic polyamide contains at least one aromatic ring and a nonaromatic species. Suitable polyamides have an article forming molecular weight and preferably an I.V. of greater than 0.4.
Preferred wholly aromatic polyamides comprise in the molecule chain at least 70 mole% of structural units derived from m-xylylene diamine or a xylylene diamine mixture comprising m-xylylene diamine and up to 30% of p-xylylene diamine and an aliphatic dicarboxylic acid having 6 to 10 carbon atoms, which are further described in Japanese Patent Publications No. 1156/75, No. 5751/75, No. 5735/75 and No. 10196/75 and Japanese Patent Application Laid-Open Specification No. 29697/75.
Polyamides formed from isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, meta- orpara-xylylene diamine, 1,3- or 1,4-cyclohexane(bis)methylamine, aliphatic diacids with 6 to 12 carbon atoms, aliphatic amino acids or lactams with 6 to 12 carbon atoms, aliphatic diamines with 4 to 12 carbon atoms, and other generally known polyamide forming diacids and diamines can be used. The low molecular weight polyamides may also contain small amounts of trifunctional or tetrafunctional comonomers such as trimellitic anhydride, pyromellitic dianhydride, or other polyamide forming polyacids and polyamines known in the art.
Preferred partially aromatic polyamides include, but are not limited to poly(m-xylylene adipamide), poly(m-xylylene adipamide-co-isophthalamide), poly(hexamethylene isophthalamide), poly(hexamethylene isophthalamide-co-terephthalamide), poly(hexamethylene adipamide-co-isophthalamide), poly(hexamethylene adipamide-co-terephthalamide), poly(hexamethylene isophthalamide-co-terephthalamide) and the like or mixtures thereof. More preferred partially aromatic polyamides include, but are not limited to poly(m-xylylene adipamide), poly(hexamethylene isophthalamide-co-terephthalamide), poly(m-xylylene adipamide-co-isophthalamide), and/or mixtures thereof. The most preferred partially aromatic polyamide is poly(m-xylylene adipamide).
Preferred aliphatic polyamides include, but are not limited to poly(hexamethylene adipamide) and poly(caprolactam). The most preferred aliphatic polyamide is poly(hexamethylene adipamide). Partially aromatic polyamides are preferred over the aliphatic polyamides where good thermal properties are crucial.
Preferred aliphatic polyamides include, but are not limited to polycapramide (nylon 6), poly-aminoheptanoic acid (nylon 7), poly-aminonanoic acid (nylon 9), polyundecane-amide (nylon 11), polyaurylactam (nylon 12), poly(ethyleneadipamide) (nylon 2,6), poly(tetramethylene-adipamide) (nylon 4,6), poly(hexamethylene-adipamide) (nylon 6,6), poly(hexamethylene-sebacamide) (nylon 6,10), poly(hexamethylene-dodecamide) (nylon 6,12), poly(octamethyleneadipamide) (nylon 8,6), poly(decamethylene-adipamide) (nylon 10,6), poly(dodecamethylene-adipamide) (nylon 12,6) and poly(dodecamethylenesebacamide) (nylon 12,8).
The most preferred polyamides include poly(m-xylylene adipamide), polycapramide (nylon 6) and poly(hexamethylene-adipamide) (nylon 6,6). Poly(m-xylylene adipamide) is a preferred polyamide due to its availability, high barrier, and processability.
The polyamides are generally prepared by processes which are well known in the art.
Although not necessarily preferred, the polymers of the present invention may also include additives normally used in polymers. Illustrative of such additives known in the art are colorants, pigments, carbon black, glass fibers, fillers, impact modifiers, antioxidants, stabilizers, flame retardants, reheat aids, crystallization aids, acetaldehyde reducing compounds, recycling release aids, oxygen scavengers, plasticizers, nucleators, mold release agents, compatibilizers, and the like, or their combinations.
All of these additives and many others and their use are known in the art and do not require extensive discussion. Therefore, only a limited number will be referred to, it being understood that any of these compounds can be used in any combination so long as they do not hinder the present invention from accomplishing its objects.
This invention also relates to articles prepared from the nanocomposite material of this invention, including, but not limited to film, sheet, pipes, tubes, profiles, molded articles, preforms, stretch blow molded films and containers, injection blow molded containers, extrusion blow molded films and containers, thermoformed articles and the like. The containers are preferably bottles.
The bottles and containers of this invention provide increased shelf storage life for contents, including beverages and food that are sensitive to the permeation of gases. Articles, more preferably containers, of the present invention display a gas transmission or permeability rate (oxygen, carbon dioxide, water vapor) at least 10% lower (depending on clay concentration) than that of similar containers made from clay-free polymer, resulting in correspondingly longer product shelf life provided by the container. Desirable values for the sidewall modulus and tensile strength may also be maintained.
The articles may also be multilayered. Preferably, the multilayered articles have a nanocomposite material disposed intermediate to other layers, although the nanocomposite may also be one layer of a two-layered article. In embodiments where the nanocomposite and its components are approved for food contact, the nanocomposite may form the food contact layer of the desired articles. In other embodiments it is preferred that the nanocomposite be in a layer other than the food contact layer.
The multilayer articles may also contain one or more layers of the nanocomposite composition of this invention and one or more layers of a structural polymer. A wide variety of structural polymers may be used. Illustrative of structural polymers are polyesters, polyetheresters, polyamides, polyesteramides, polyurethanes, polyimides, polyetherimides, polyureas, polyamideimides, polyphenyleneoxides, phenoxy resins, epoxy resins, polyolefins, polyacrylates, polystyrene, polyethylene-co-vinyl alcohols (EVOH), and the like or their combinations and blends. The preferred structural polymers are polyesters, such as polyethylene terephthalate and its copolymers.
In another embodiment of this invention, the polymer-clay nanocomposite and the molded article or extruded sheet may be formed at the same time by co-injection molding or co-extruding.
Another embodiment of this invention is the combined use of silicate layers uniformly dispersed in the matrix of a high barrier thermoplastic together with the multilayer approach to packaging materials. By using a layered clay to decrease the gas permeability in the high barrier layer, the amount of this material that is needed to generate a specific barrier level in the end application is greatly reduced. Since the high barrier material is often the most expensive component in multilayer packaging, a reduction in the amount of this material used can be quite beneficial. With the nanocomposite layer being sandwiched between two outer polymer layers, the surface roughness is often considerably less than for a monolayer nanocomposite material. Thus, with a multilayer approach, the level of haze is reduced.

Polymer/clay nanocomposite having improved gas barrier comprising a clay material with a mixture of two or more organic cations and a process for preparing same

University of South Carolina Research Foundation


A method and system for automatically loading and unloading a transport is disclosed. A first guidance system is used to travel near the transport and a second guidance system is used to travel on the transport.

The present invention is generally directed to material handling vehicles and, more particularly, to an automatic guided vehicle that is capable of automatically loading and unloading a transport, for example, a tractor trailer, a rail car, a flatbed trailer or a shipping container.
Automatic guided vehicles (AGVs) are used throughout the material handling industry to transport loads. The term AGV is commonly used to refer to robust vehicle designs having any of a number of available automated guidance systems. Automatic guided carts (AGCs) is a term commonly used to refer to a less robust vehicle used for similar but less complicated applications. Throughout this application, including the claims, the term AGV shall mean and include both AGV's and AGC's, as well as any other vehicle that is automatically guided.
Current AGV designs generally include a frame with swivel castors located at the four corners of the frame. Other features may include a drive wheel assembly and rigid castors for directional control of the cart. In one current design, two rigid castors are fixed to the frame and located approximately midway between the swivel castors on each side of the cart frame. The two pair of swivel castor axes and the rigid castor axis are generally parallel to each other. The steerable driving unit is attached to the cart frame, generally by way of a plate that is hinged and spring loaded from the cart frame to ensure that the steerable drive wheel maintains adequate traction with the support surface. In another embodiment, a fixed drive wheel propels the AGV and a steerable castor wheel directs the movement of the AGV.
An AGV includes a guidance system that controls its movement. Known guidance systems in use today include wire guidance, laser guidance, magnetic tape guidance, odometry guidance, inertial guidance and optical guidance, and each have their own associated positives and negatives. For example, inertial guidance is susceptible to tracking errors, where the travel distance and direction measured by the AGV differs from the actual distance and direction of travel. Though they can be minimized, tracking errors may compound over long travel distances and the system must adjust for these errors, for example, by utilizing waypoint reference markers (magnetic paint, Radio Frequency Identification (RFID) tags, etc.) along the designated path.
Laser guidance systems use special markers that the AGV senses and uses to control its travel. This type of system is susceptible to obstruction of markers and, most notably, requires markers to be present in any environment of travel. If the path of the AGV is modified, the markers must be physically moved. Further, an AGV with this type of guidance system can only travel in areas that have these special markers, which, in the context of this invention, requires that any transport to be loaded or unloaded include markers.
One difficulty associated with the automatic loading and unloading of a transport is the varying position of the transport in relation to the fixed loading dock position. Transports are usually positioned manually, for example by a driver in the case of a truck. This manual positioning results in an unknown variability in the position of the transport. As a driver positions the trailer at the loading dock, he or she may be unable to perfectly square the trailer with the dock door. This will leave the trailer at a skewed angle in reference to the dock door. Since the angle is unknown and can vary at each positioning at the dock, an AGV cannot effectively guide and deliver loads in the trailer without having the capability of detecting and compensating for this trailer skew. The prior art has addressed this problem by using skid plates to position the transport in relation to the loading docks, however this is a costly and inefficient process.
Another difficulty associated with the automatic loading and unloading of a transport is that the AGV must be able to overcome the difference in height between the transport and the dock. Different types of transports, as well as different styles of the same transport, will vary in height. Furthermore, the height of a particular transport is not static; as trailer is loaded the suspension will compress, resulting in a change in the height of the transport. In order to allow robust operation, the AGV must be able to operate with varying transport height and, therefore, varying height differences between the transport and dock. The prior art has addressed this problem by using hydraulic or other types of jacks to stabilize and level the transport, however this is another costly and inefficient process.
The use of a loading ramp between the dock and the transport is often used to ease the transition between the two. However, a steep incline or decline between dock and transport can cause guidance difficulties. For example, an AGV that uses a laser guidance system may lose the target as it moves up an incline, or down a decline, due to the fact that the laser will be pointing either above or below the target.
The variability in position of the transport may prohibit the automatic loading of the truck, and almost certainly will reduce its efficiency. For example, the most efficient loading process positions the loads as closely to each other as possible, and any variability in the expected position of the transport will tend to increase the separation of the loads.
Despite the use of guidance systems to control travel of an AGV, their use in the process of loading and unloading loads from a transport has yet to be satisfactorily addressed in the art.

Automatic transport loading system and method


An annunciating apparatus comprises a toilet tank containing water and an electrical circuit within an enclosure. Extending upwardly from the enclosure, an arm terminates with a hook engaging the toilet tank for suspending the enclosure in a position just below the toilet tank. The electrical circuit provides a source of electricity, an activating circuit, a sound producing circuit, a sound selecting circuit, an amplifying circuit and a speaker. This circuit is enabled for producing a selected sound from the speaker when the toilet tank is flushed. Two modes are possible; one where the sound is initiated by the water in the tank dropping during flush, and the second when a selected flush related sound is picked up.

1. Field of the Invention
This invention relates generally to mechanized announcement or sound producing devices and more particularly to such a device as used with a toilet.
2. Description of Related Art
The following art defines the present state of this field:
Findley, Jr., U.S. Pat. No. 2,721,531 describes a toilet signal device for training infants comprising a toilet seat, a signal device, and actuator for said signal device terminating in a substantially hooked portion, hooked means extending from the other end of said toilet seat and carried by the latter, and a disposable trip supported at each end by said hooked portion of said actuator and said hook means.
Lee, U.S. Pat. No. 3,059,608 describes a training chair comprising a child's chair construction having a seat provided with an accommodation opening, a normally horizontal load-responsive downwardly tilting receptacle, means fixed to the chair structure in a plane below the seat pivotally suspending said receptacle below and in alignment with said opening with the upper portion normally spaced below the underneath side of said seat, a tripping lever constituting a load-responsive normally balanced beam and being provided with adjustable balancing means, means supporting said lever for pivotal movement, said lever and means being offset relative to a rearward tilting portion of said receptacle, a load responsive terminal at one end of said lever upon which a minimal marginal portion of the bottom of said receptacle is supported, free-turning rotating force multiplication motion transmitting means, and flexible means associated and operatively connected with said last named means providing forces for the actuation of a sound emitting signaling device mounted cooperatively on said chair.
Garthofner, U.S. Pat. No. 3,172,390 describes a toilet training chair comprising supporting sides and a seat connected therebetween, said seat having an opening, a planar surfaced support member, means pivotally mounting the support member to said sides beneath the seat, tensioned spring means disposed forwardly of the pivotal mounting means connected to the seat and the support member for urging the support member to a substantially horizontal position with respect to the seat, a receptacle positioned on said support member below said opening, a musical device having a gravity operated actuating member mounted on one of said sides, and an upright control member carried by said support member cooperating with said actuating member for normally holding the actuating member in a raised inoperative position and permitting the musical device to be operated when the support member is caused to pivot downwardly by the introduction of a waste product into said receptacle whereby the control member is moved away from said actuating member to thereby permit said actuating member to be lowered under its own weight to actuate the musical device.
Kraff, U.S. Pat. No. 3,715,549 describes a conventional water closet having a water box, bowel, and flushing means, there is provided a music box or sound emitting device which will produce a pleasant sound in response to manual flushing of the water closet.
Warrington, U.S. Pat. No. 4,849,742 describes a signaling device that is actuated for a limited period of time if a toilet seat cover is not promptly lowered following flushing of the toilet. In the preferred form, an electrically operated signaling device is coupled to an electrical power source through a magnetically actuated switch at the front of the toilet tank and also through a second switch. A magnet fastened to the seat cover closes the magnetically actuated switch when the cover is in the raised position and movement of a float in the toilet tank in response to flushing closes the second switch for a limited period following initiation of flushing. The device reminds users of the toilet to close the cover. This avoids discomfort to a subsequent user of the toilet and assures that small children and pets are blocked from the toilet bowl.
Bogstad, U.S. Pat. No. 4,896,144 describes a warning system that is adapted to warn someone to wash their hands prior to leaving or entering a facility in which hand washing is important. The system includes a door activated system that can be either visible or audible or both and can include a door locking system and a remote signaling system. The warning system is armed when the door is opened to permit entry into the facility and is de-activated upon the actuation of hand-washing facilities. In one embodiment, the system is used in a bathroom and the warning system can be activated by the flushing of a toilet.
Butts, U.S. Pat. No. 5,560,051 describes a sound-generating toilet training device for use with a conventional potty chair comprising a self supporting base member having a generally planar top face and a bottom face, the base member is adapted to be removably received within a receptacle of the potty chair, an actuating member is positioned on the top face for actuating an electronic circuit, the actuating member including a pair of interleaved contact members insulated from each other, a generating member coupled to the actuating member is also provided for generating an output signal, the generating member being sealed against fluid contact and an emitting member, the emitting member is responsive to the output signal and emits an audible sound, the generating member and the emitting member are positioned on the base member whereby when the device is positioned within a potty chair receptacle and a child urinates thereon, the contact members are caused to be bridged by the urine enabling an output signal to be generated that is emitted as an audible sound for the enjoyment of the child.
Dunford, U.S. Pat. No. 5,573,407 describes an apparatus and method for training a child to complete a toilet training experience. The invention includes an object placed in close proximity to a toilet appropriate for training the child. The invention also includes a device for emitting a musical sound. Upon successful completion of a toilet training experience, the child is provided a reward token, such as a coin. The child may then place the token into the object, which may comprise a piggy bank. In response to placement of the token into the object, the music emitting device generates a musical sound. The method allows the child to associate the object visually with the training experience and to associate the musical sounds audibly with the training experience.
Hinkel, U.S. Pat. No. 6,870,015 describes a toilet instruction method and apparatus in which toilet use is monitored and one or more audible messages is produced which instruct users of the toilet regarding next steps in toilet use and hygiene. The apparatus includes a housing which is removably attachable to the toilet. A switch arm extends from the housing and is coupled with the toilet flush handle. An audio speaker is partly enclosed within the housing and produces the audible messages. Electronic circuitry enclosed within the housing receives a switch activity signal indicative of the position of the switch arm and responsively activates production of the audible messages. The electronic circuitry includes a message storage unit for storing a plurality of messages.
Machre, U.S. Pat. No. 6,028,520 describes an enunciator for training individuals in toilet etiquette and sanitation. The enunciator has a small housing that hangs on the side of the toilet tank, is incorporated into the seat of the toilet or hangs from the flush handle of the toilet. The housing is preferably plastic and can be animal shaped, for example, like a frog. A sound module, batteries, internal sensors, controller and speaker are mounted in the housing and the controller is connected to the external sensors by electrical wires. A small light such as an LED can be included to indicate that the unit is working. The sensors detect a person near the toilet, the position of the toilet seat (lowered or raised), a person sitting on the seat, and operation of the flush handle. The controller decides what messages to play based on the sensed conditions. Additionally, the housing may contain a small separate tape player for music or prerecorded humorous sounds. The tape player is controlled by the enunciator to coordinate with any played messages. An on/off switch and volume control are also provided.
Vlahos et al., U.S. Pat. No. 6,417,773 describes a system for encouraging good personal hygiene in toilet facilities, including means for detecting the acoustic signal generated by the inrush of water into a toilet bowl to trigger a recorded admonition to the toilet user to cleanse his or her hands.
Glew, AU 408193, describes a toilet training device comprising a dry pan receptacle, moisture responsive electrode means located in the base of the receptacle, electric control means detachably connected to said electrode means, and musical production means operably controlled by said electric control means such that when the electrodes are bridged by liquid or moisture in the receptacle a circuit of said electric control means is completed by thereby actuate said musical production means.
Katsuyoshi, JP 10317456 describes an imitation sound generator, in which flush water is not consumed more than required and an imitation sound can also be used comfortably as the sound of natural feeling. The device is annexed to a flush water tank 3 for flushing a stool connected to a water supply piping, and has a detecting means detecting a user at a time when a flushing imitation sound is generated in response to the time of easing nature and a water supply means supplying the flush water tank 3 with water by a signal input from the detecting means. A standby period, when a supply water level to the flush water tank 3 from the water supply piping is kept low and the generation of an imitation sound is prepared, and an imitation-sound operating period, when supply water by the water supply means is discharged from a section upper than the supply water level during the standby period on the basis of the signal input from the detecting means after the standby period, are repeated.
Katsuyoshi, JP 11140938 describes a sound-effects generator by which a sound-effect due to an actual flow of flushing water can be obtained in a simple device regardless of the existence of a washing water tank such as a low tank. This sound-effects generator is provided with a recovery pipe 7 of which the upper end of the passage is positioned in the inside of a sound-effects chamber 5b which can hold water and of which the upper level is set to be the maximum water storage level in the second-effects chamber 5b, a water supply pipe 6 of which the upper end of the passage is positioned above the upper end of the flow passage of the recovery pipe 7 and of which the delivery direction faces the water storage face side, and a solenoid valve 8 incorporated halfway in the water supply side pipe 6. The water supply pipe 6 is connected to the upstream of the valve opening/closing the passage, provided in the passage way for supplying washing water to a flushing toilet seat and the recovery pipe 7 is connected to the downstream thereof.
Toto, LTD., JP 2000314168 describes enhancing imitation sound effect and improving the operation and execution by incorporating an imitation sound device in a toilet stool. A space part 5 in the rear part of a flushing valve flushing type flush toilet 3 is molded integrally with a flushing water toilet stool 3, and an imitation sound device 1 is incorporated in the space part. For instance, an opening part 6 communicating with the space part 5 is provided on the side of the flushing water toilet stool body 3, and the sound generation part such as a speaker of the imitation device 1 is provided by facing the opening part 6. In addition, the operation part 2 of the sound imitation device 1 is attached to the wall face 9 of a toilet. In the case where the imitation sound device is not projected to the outside of the flushing water toilet stool 3 and the operation part or the like of a warm water flushing device is installed adjacently by providing it in the space part 5 of the flushing water toilet stool 3, they are not treated as a nuisance. A sound generated from the imitation sound device 1 can be heard to have no sense of incompatibility with a flushing sound flowing from the flushing water toilet stool 3. In addition, since the imitation sound generation part is incorporated in the inside of the toilet stool, the arrangement of the remote control operation part or the like of other devices is facilitated.
The prior art teaches toilet signaling devices having music and other sounds for training children, mechanically tripped when flushing action occurs or related to seat or lid position, related to hand washing, with receipt of a token, sensed motion, water rushing sound, by water level, but the prior art does not teach such a device with choice of sound and activation through toilet actuation noise or water flush, and which is easily hung on a toilet tank. The present invention fulfills these needs and provides further related advantages as described in the following summary.